Contraception: a risk factor for endometriosis.

Endometriosis was detected in 42 cases out of 566 patients undergoing laparoscopic tubal sterilization. The presence of endometriosis was then correlated with previous contraception. Those patients using no contraception, or barrier contraception alone, were regarded as controls. Previous oral contraceptive use was associated with a lower incidence of endometriosis, although the difference was not significant. A significantly higher incidence (P less than .05) of endometriosis was present in former intrauterine device users, possibly because of retrograde flow of increased menses.